Locking nut



FIG. 1 is perspective view of a locking nut which illustrates my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof, the right side elevational view being a mirror image thereof; and,

FIG. 5 is a top plan view thereof, the bottom plan view being a mirror image thereof. 

The ornamental design for a locking nut, as shown and described. 